You can’t be a Melbourne theatre critic for long without stumbling on a badly kept secret – artists with disability produce some of our finest work for the stage. Over the last few months, Back to Back’s Ganesh vs The Third Reich has taken out The Age Critics Prize at the Melbourne Festival, and local company Rawcus made Small Odysseys, world-class visual theatre performed on a massive scale at the Arts House Meat Market. No one who has followed these companies could be surprised at their achievements.

In the wake of Site UnSeen, a piece of community promenade theatre – made with the homeless – that managed to exploit the vulnerable and insult its audience, it is worth looking at why Back to Back and Rawcus succeed. Both companies offer profound examples of how to negotiate the challenges and reap the rewards of making art with marginalised performers.

They also constitute a powerful argument for properly resourced ensemble theatre. They’re the slow food of the theatre world – a showcase of the richness and nuance that comes from long-term collaboration between artists, and a slow-burn development process measured in months and years rather than weeks.

Though their style of theatre is quite different, Back to Back and Rawcus share a sense of adventurousness, a command of presence and a frisson of unpredictability, a willingness to embrace risk and, crucially, the critical rigor to make that risk pay off in aesthetic terms.

It doesn’t get riskier than Ganesh vs The Third Reich. The idea of a Hindu god traipsing through Nazi Germany, much less creating mythic theatre from the Holocaust, was always going to generate controversy. Perhaps only Back to Back could have gotten away with it.

I was offended when a colleague suggested that I gave the show five stars because the performers had disabilities. But there is some truth in it. Who the performers are is an integral to the work. Without performers with disability, would Ganesh have been able to so effectively dramatise the velvet glove of political correctness, and the ugly fist of discrimination? Could the show have broached the Holocaust in the same way if it didn’t know that the Nazis, with their sinister eugenic creed, would have thrown some of these performers in gas chambers?

Disability may present significant barriers in society, but it can be turned to staggering advantage on stage. History provides many examples where disability is the basis for unusual talents and freedoms in the arts. The dangerous political theatre of Back to Back seems to carry within it some shade of the Shakespearean Fool – licensed to tell unpleasant truths that anyone with a place in the social hierarchy would be punished for.

In Small Odysseys, Rawcus embraced another strand of culture that merges disability with creativity. It was a beautiful reimagining of Homer that took what we traditionally think of as disability and showed how blindness can sharpen our ears to the Muse’s song.

It’s fascinating how organic the sound and lightning design feel in Rawcus’ work. Some performers rely absolutely upon the designers. Those with short-term memory impairment, for example, respond to tricks of the light or specific musical cues – a level of integration between design and performance that’s quite unique.

Yet the work of these artists isn’t ‘disability theatre’ so much as a stirring assertion of common humanity, a celebration of the fact there are many ways of being in the world. As the Artistic Director of Rawcus, Kate Sulan, puts it: “I hate it when theatre is like Neighbours … I love seeing different body shapes, diverse abilities – when the stage looks a bit more like that big old world out there.”

It’s a vision that is only slowly being realised. The first production of the MTC’s 2012 season, Nina Raine’s Tribes, stars a deaf performer. The artistic leadership shown by the likes of Back to Back and Rawcus can claim some small credit: they have blazed a trail that leaves some of our other theatre companies for dead.